President Obama ran — and won — in 2008 on the idea of uniting the country. But each of his first three years in office has marked historic highs in political polarization, with Democrats largely approving of him and Republicans deeply disapproving.

View Photo Gallery: President Obama is gearing up for what could be a bruising reelection fight.

For 2011, Obama’s third year in office, an average of 80 percent of Democrats approved of the job he was doing in Gallup tracking polls, as compared to 12 percent of Republicans who felt the same way. That’s a 68-point partisan gap, the highest for any president’s third year in office — ever. (The previous high was George W. Bush in 2007, when he had a 59 percent difference in job approval ratings.)

What do those numbers tell us? Put simply: that the country is hardening along more and more strict partisan lines.

While it’s easy to look at the numbers cited above and conclude that Obama has failed at his mission of bringing the country together, a deeper dig into the numbers in the Gallup poll suggests that the idea of erasing the partisan gap is simply impossible, as political polarization is rising rapidly.

Out of the ten most partisan years in terms of presidential job approval in Gallup data, seven — yes, seven — have come since 2004. Bush had a run between 2004 and 2007 in which the partisan disparity of his job approval was at 70 points or higher.

“Obama’s ratings have been consistently among the most polarized for a president in the last 60 years,” concludes Gallup’s Jeffrey Jones in a memo summing up the results. “That may not be a reflection on Obama himself as much as on the current political environment in the United States, because Obama’s immediate predecessor, Bush, had similarly polarized ratings, particularly in the latter stages of his presidency after the rally in support from the 9/11 terror attacks faded.”

Our guess is that Jones’ latter hypothesis is the right one — that we are simply living in an era in which Democrats dislike a Republican president (and Republicans dislike a Democratic one) even before the commander in chief has taken a single official action.

The realization of that hyper-partisan reality has been slow in coming for Obama. But in recent months, he seems to have turned a rhetorical corner — taking the fight to Republicans (and Republicans in Congress, particularly) and all but daring them to call his bluff.

Democrats will point out that Republicans in Congress have played a significant part in the polarization; the congressional GOP has stood resolutely against almost all of Obama’s top priorities. And Obama’s still-high popularity among the Democratic base also exacerbates the gap.

For believers in bipartisanship, the next nine months are going to be tough sledding, as the already-gaping partisan divide between the two parties will only grow as the 2012 election draws nearer. And, if the last decade of Gallup numbers are any indication, there’s little turnaround in sight.

For a rebuttal of our analysis of the Gallup data, make sure to check out this post written by longtime Democratic Senate staffer Jim Manley.

Romney says Gingrich has hurt himself: Trying a new tack in Florida, Mitt Romney said Newt Gingrich’s fall in the polls is his own fault.

“The people of Florida have watched the debates and listened to the speaker and listened to the other candidates and said, ‘You know what? Mitt Romney is the guy we’re going to support,’” Romney said at a rally in Naples.

“I think each of us, if we fail somewhere, if we fail in a debate, if we fail to get the support of people, it’s time to look in the mirror,” Romney said.

Gingrich has complained over the last week about an applause ban at a debate, has accused Romney of lying about his record, and has lashed out at the GOP “establishment,” which he says is out to get him.

“I am extremely uncomfortable with the extended use of my personal image in this political ad,” Brokaw said in a statement. “I do not want my role as a journalist compromised for political gain by any campaign.”

The report describes Gingrich’s reprimand by the U.S. House in 1997 for using tax-exempt money for political purposes and giving the House Ethics Committee false information.

Kerrey buying property in Nebraska: Former senator Bob Kerrey (D-Neb.) tells The Fix that he is buying property in his former home state of Nebraska, but that it doesn’t mean he will seek a return to the Senate in the Cornhusker State.

Kerrey left Nebraska after retiring from the Senate and at one point flirted with the idea of running for mayor of his new home, New York City, where he headed up the New School university.. That’s something Republicans are likely to use against him if he opts to run for retiring Sen. Ben Nelson’s (D-Neb.) seat.

But if he does run, Kerrey will have a Nebraska address from which to do it. A senator must live in the state he or she represents.

In response to The Fix’s inquiry, Kerrey confirmed he was buying a place in Nebraska: “Yes, but it really isn’t a signal that we have decided to re- enter politics.”

“Almost all my family is in Nebraska so we need a place to gather when I am back,” he added.

Kerrey is considered the Democrats’ best hope of holding what is arguably their toughest Senate seat to defend.

Gingrich broaches brokered convention: Despite his troubles in Florida, Gingrich says the GOP presidential contest will continue for months and that Romney may not get enough delegates to win outright at the convention.

“When you add the two conservatives together we clearly beat Romney,” Gingrich said, according to the Wall Street Journal. “I think Romney’s got a very real challenge trying to get a majority at the convention.”

As our great delegate tracker shows, a candidate needs more than half of the 2,286 available delegates to win the nomination. If no candidate gets that number, the GOP would go to its convention later this year without a defined nominee.

Rep. Ron Paul (R-Texas) has already aimed to stay in the race for the long haul and build up delegates, but a third candidate would likely need to stay in the race and amass delegates to prevent Romney from getting a majority.

Santorum leaves trail with daughter hospitalized: Rick Santorum left the campaign trail after his his 3-year-old daughter, Bella, was hospitalized this weekend with pneumonia.

Santorum skipped an appearance on NBC’s Meet the Press and campaign events Sunday to tend to Bella, who has a rare genetic disorder and has undergone frequent treatment and multiple surgeries.

In Santorum’s stead, his 20-year-old daughter Elizabeth and the Duggar family, from TLC’s “19 Kids and Counting,” have been traveling around Florida, and Santorum held two teleconferenced events Sunday evening.

Late Sunday, Santorum said Bella had experienced a “miraculous turnaround,” and that he will return to the campaign trail as long as her progress continues. He did not say whether he would return to Florida, where he has struggled to compete with Romney and Gingrich.